Problem: $\left(\sqrt{17.8}\right)^2=$
Taking the square root and squaring are inverse operations. So, the square root of any number squared is that same number. As an easier example, let's evaluate $\left(\sqrt{9}\right)^2$ : $\phantom{=} \left(\sqrt{9}\right)^2$ $= \sqrt{9} \cdot \sqrt{9}$ $= 3 \cdot 3$ $= 9$. Similarly, $\left(\sqrt{{17.8}}\right)^2 = {17.8}$.